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Let's begin by looking at screen my Wall Street my wall reading and writing is handled by something

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called streams and a stream is basically a connection between a program and a data source or sink under

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just basically represented by a class and it is also specific to the type of source or sink.

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For instance if source or sink is a file then we use a specific type of stream.

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Similarly when dealing with network a different type of stream is used to work a stream can be either

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an input stream or an output stream if you want to read some data from a source then you would use an

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input stream.

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Similarly if you want to write some bakeware destination then you would use an output stream and when

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working with streams there are three operations that are involved Huston's to open a stream.

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Second would be to read or write data depending on whether the open stream is input output.

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That is if you are dealing with an input stream then we would read data from the input stream on and

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off streams and conter But if we are dealing with an output stream then we simply write the door to

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open output stream.

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Finally we close the stream closing the stream would free up the system resources that the stream would

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be using and this would help in awarding resources on system resources would be things like sockets

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or file handles on the operating systems have limits on the number of sockets or file handles that can

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be open.

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So when we are done using a stream it is important to close it so that the associative system resource

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will also be released.

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Otherwise those resources will remain open and at some point we will not be able to create any new streams

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not to cross the stream for sure we can close it inside a finally block.

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And we wanted to discuss this when discussing finally block in the exceptions chapter.

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We know that a finally block will always be executed regardless of whether or not there is an exception

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.

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And here's an example of a standard template for opening and closing streams.

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And we looked at the specific goal when discussing try with resource a statement.

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But let's discuss it one more time here.

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The input stream is a file input stream.

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I need the tools for reading data out from behind.

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And one of the follow Plaisance even look at file input stream in more detail here within the try block

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we are creating an instance of filing puts strain on that basically is nothing but opening the input

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stream.

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Let's not worry about the read operation but we will see later on here when we are creating the file

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input stream object the constructor of the file input stream class can throw a file lock one exception

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which we know is a checked exception and so we have this catch block to handle it.

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The closing of the stream is done in the finally block by invoking the last method on the input stream

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object.

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No not is that within the finally block.

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We have one more try catch block and thats because a close method can also throw an Iowa exception.

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Moreover we are also checking that the reference variable in is not known if it is not null.

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Only then we close the string not that variable in can be NULL if the final input stream object could

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not be created.

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That is a file not one exception was generated when we were trying to create file input stream object

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on video distric we could get a null pointer exception when the Close method is invoked.

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Now as you can see this whole finally block looks very ugly with the end try catch block under additional

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logic so to avoid this we know that we can make use of the drive with resources statement which was

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introduced in July 7 on here is the same code with private resources which is much cleaner.

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The finally block we know that with this syntax the cleanup operation is taken care of.

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Implicitly there is a close method is invoked implicitly and we know that in reality the compiler inserts

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the time finally block into the bytecode.

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So even if an exception is generated the Close method is still in work just as in the case of using

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a finally block explicitly.

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Just recall that the object in the parenthesis should be auto closer than that is it implements the

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auto plausible interface or not the variable and is also implicitly final on this particular feature

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is also referred to as Automattic resource management or shock.

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Here is another example where multiple streams are being created within the Cripe parenthesis here the

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stream creation experience must be separated by semi-colons one instance where you would be using multiple

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streams is when we want to read data often on one stream and write it with a different stream.

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That is you are doing some kind of a file transfer.

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A lot of you will also see a table of such kind of a file transfer.

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So if you know understand what streams are on how they can be opened and closed.

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Next thing Binoy is that streams are off two types byte streams uncharacteristic is the reason for having

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these two types of streams is because Joe differentiates between processing codirector data and everything

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else who process character data like text classes that fall under characteristics are used on the process

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non character data like Lexa images process underbite streams are used.

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This record shows the base classes for both byte streams as well as character streams for instance input

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stream is the biggest class for all byte oriented input streams.

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One reader is the base class for all character oriented input streams.

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So most of the stream I will classes that reading and writing will directly or indirectly subclassed

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these base classes.

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So that's an interaction between my will in the next couple of lessons.

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We will focus on byte streams after which we would look at character issues.

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Thank you